Medical devices requiring portable power supplies, for example batteries, are ubiquitous in modern medical treatment facilities. Medical devices may have their power supplies fully integrated into the medical device, whereas other medical devices may have removable power supplies. Either the medical devices themselves or batteries used for them need to be recharged or changed as a result of use. Medical devices and/or batteries can be placed in charging devices in order to replenish the stored charge. There can be an indication on the medical device, the charging device, the battery, etc. of the level of charge contained in the medical device or battery.